Apparatus for blowing scale from pipe



Filed Sept. 24, 1941 3 Sheets-Sheet l laweizfoiv 650 955 5A/5000A4 J78,

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Filed Sept. 24, 1941 3 Sheets-Sheet 2 TUNE W i a I A A E Q Q -1% S .l iIL I 1L Q &

Oct. 31, 1944. A G SNE D JR 2,361,660

APPARATUS FOR BLOWING SCALE FROM PIPES Filed Sept. 24, 1941 3Sheets-Sheet 5 hzaeizforx Patented Oct. 31, 1944 UNITED S T APPARATUSFOR BLOWING SCALE FROM PIPE George Sneddon, Jr., McKeesport, Pa..,assignor to National Tube Jersey 6 Company, a corporation of NewApplication September 24, 1941, Serial No. 412,167

' 3 Claims.

In accordance with the present invention, there is providedimprovedmechanism for removing scale or the like from steel surfaces.The formation of this scale is a Well-known occurrence, it resultingprincipally from oxidation of the surfaces during the treating andshaping of the steel. This scale maybe attached firmly to the steelsurface, or it may become loosened Or dislodged during handling. Itspresence is undesirable both to manufacturer and to consumer.

Where the scale is in the interior of pipes or similar tubular objects,the detached portions of the scale, with at least a substantial amountof other loosened scale, maybe blown out with a jet of air passing underpressure through the interior of the pipe, the air; being introducedfrom a nozzle inserted into the pipe and attached to one end of aflexible hose. The air supply to the nozzle is controlled by ahandoperated valve with a pistol grip and trigger gnp.

Specifically, the present invention relates to the above-indicated typeof equipment, it providing certain improvements in the nozzleconstruction and control instrumentalities, as will be pointed out ingreater detail hereinafter.

Further objects ofgthe invention will be apparent as the descriptionproceeds, and the features of novelty will be pointed out inparticularity in the appended claims; and it will be understood that thespecific embodiments of the invention as are described and illustratedherein are intended only by way of illustrating one form of theinvention which is subject to various alterations, modifications, orrearrangement of parts as may become necessary to adapt the invention tovarying conditions and uses, as defined by the appended claims.

The invention will be understood more clearly by reference to theaccompanying drawings, in which:

Fig. 1 represents an assembly view of the improved apparatus, indicatingdiagrammatically fluid control circuits for the mechanism;

Fig. 2 represents aside elevation of the apparatus partially in section,showing details of the nozzle assembly;

Fig. 3 represents a longitudinal sectional ele. vation oi the actuatingcylinder showing details of construction; 6

Fig. 4 is a longitudinal sectional elevation of the nozzle assembly, theview being on a larger scale than in the showing of Fig. 2, and showingthe nozzle in operative position;

} ence number 22.

Fig. 5 is a sectional elevation of the left-hand end of the machine asviewed in Figs. 2 and 4, the view being taken on the section line 5-5 ofFig. 2, looking in the direction of the arrow;

Fig. 6 is a similar view of the right hand end of the apparatus, theview being taken on the line. 6--6 of Fig. 2 looking in the direction ofthe arrows;

Fig. 7 is a view similar to Fig. 4, but showing a modified nozzleassembly;

Fig. 8 is a diagrammatic view illustrating the action of a control valveforming a part of the improved apparatus of this invention.

Referring more particularly to the drawings, it will be observed thatthe machine of the present invention comprises a nozzle assembly whichis indicated generally at A and an actuating assembly B. This actuatingassembly B is adapted to receive compressed air from suitable air linessuch as are shown in Fig. 1, to which detailed reference may now bemade.

It will be seen that the mechanism of the present invention is mountedon an operating table which is indicated generally at C and which iscomposed of a suitable number of rails on the top of which, as indicatedat I0, is inclined, so that the pipes or other articles to be treatedmay roll to the treating station. Suitable rollers, one of which isillustrated at [2, are provided, each of the rollers preferably beingprovided with anti-friction bearings. These rollers facilitate thehandling of pipe and contribute to the speed of the operation.

The air supply line is indicated at M, in which is posted a pressureregulator l6 which is adapted to maintain a constant pressure in theactu' ating assembly B, which will be described hereinafter. A flexiblepipe l4 connects the pressure regulator Hi to the actuating assembly B.

A pipe l8 connects into the pipe M, a branch 20 leading from this pipe18 into a three-way valve which is indicated generally by the refer- Thevalve 22 is provided with a pipe 24 which connects with the actuatingassembly B for the purpose hereinafter set forth. Also, the valve 22 isprovided with an additional pipe indicated generally 28, the operationor which is indicated diagrammatically in Fig. 8, which view shows thepipes 20, 24 and 28 as joining in the valve. These pipes are allcontrolled by the three-way valve 22, which may be any suitable standardthree-way valve, the operation thereof being shown only in a generallydiagrammatic manner in Fig. 8.

The pipe I8 is connected to a supply pipe 88 which enters the actuatingassembly 13 through the right end thereof, when viewed as in Fig. 2. forexample. This pipe 38, therefore, is connected to the main supply lineI4, and is adapted to deliver the full line Pressure to a nozzleassembly A. The line 24 from the valve 22 enters the right hand portionof the actuating assembly B at the top thereof, as viewed in Fig. 2,while the line I4'enters the left hand portion of the actuating assemblyB, and is adapted to deliver air under constant pressure to the lefthand portion or the actuating assembly. Pipe lines I4, I8, 28, and 24are all flexible, the reason for which will become apparent hereinafteThe actuating assembly now will be described in detail, and for thispurpose reference may be made to Fig. 3.

It will be seen from this view that the actuating assembly includes ahousing 32 provided with bushings 34 and 36 into which the pipes l4 and24 conveniently are threaded.

It will be seen further that the pipe 88 passes through a screw-plug 38,and through a bearing portion 48 of the housing, this portionbeingacasting having a hole through which the pipe 38 passes. Also, thebearing portion 48 of the housing is provided with a hole 42 which ismachined, as shown, part way through the casting and communicates with ahole 44 into which the pipe 24 opens, the resulting juncture making aduct which extends through the casting for supplying air from the valve22 into the actuating assembly B and behind a plunger head assembly D,which operates in a piston chamber referred to in more detailhereinafter.

This assembly comprises a sleeve 48 provided with a flange or collar 48,the sleeve and collar being fitted over the pipe 38 and retainedsuitably thereon, as by shrinking the sleeve on the pipe. The sleeve 48also is provided with an enclosing sleeve 58 having a flanged abutmentcollar 52 which is adapted to engage the collar 48 and defines aretaining flange or seal for a suitable yieldable packing 54. Thispacking 54 is held in place by a ring 56, against which is secured asecond similar washer 58, by means of a collar 88, which is threaded onthe pipe 38 and is positioned against the sleeves 48 and 58 and the ring58 so as to secure the resulting assembly in tightly assembledrelationship.

The plug 38 retains suitable packing 82 in position which may beimpregnated with graphite or other lubricant, and forms an additionalseal against air leakage; this packing thereby facilitating the movementof the pipe 38.

This construction is duplicated in the other end of the actuatingassembly. Pipe I4 enters a hole 44' which communicates with a hole 42 incasting 48' thereby forming a duct for admitting air into the plungerchamber under substantially constant pressure, this chamber being thespace between the bearing castings 48 and 48', this chamber beingdivided into forward and rear compartments by the plunger head assemblyD.

A screw-plug 84, similar to plug 38 has likewise an annular hole throughit through which hole the pipe 38 is passed. The plug 64 retains packing88 in place, this packing being similar to the packing 62.

It will be seen that since pipe I4 receives air automatically maintainedunder substantially constant pressure, such air under constant pressureis transmitted into the forward compartment of the plunger chamber, sothat the plunger head assembly D always works against this pressure as acushion.

Likewise, air is admitted under pressure through the pipe 24 into therear compartment of the plunger 'chamber. However, this air passesthrough the three-way valve 22, and consequently, under the manualcontrol of the operator oi the machine, who can build up and release atwill the pressure in this reafcompartment so as to maintain a positiveor negative pressure differential with reference to the constantpressure in the' opposing chamber. This causesthe plunger head assemblyto move towards the chamber containing the less pressure. This movementmoves the pipe 38 accordingly, and the purpose of this forth and back orreciprocating movement will become apparent as the description proceeds.

Now if, for example, the valve 22 is open so as to supply a pressure or100lbs. through the pipe 24, and behind the collar; 88, while the lineI4 is supplying a constant pressure of, for example, 58 lbs. throughline I4 because of the action of pressure regulator I8, it will be seenthat the entire plunger assembly D and the pipe 38 will be moved to theleft as viewed in Figure 3, the flexible hose I8 allowing this movement,which is cushioned because of the air being admitted through the pipeI4.

The pipe 38 is threaded as is shown at I8 for the attachment of a valvesection 12, which in practice forms a continuation or the pipe 38.However, the section 12 is divided internally into two compartments by apartition 14 which extends across the inside of the section, and blocksthe flow of fluid through this section. Ports, however, are provided, asare indicated at I6 and I8, on both sides of this partition. A nozzle 88is threaded into the free end of the section 72.

Enclosing a portion of this section is a sleeve 82 which is provided atone end with an internal flange 83 which spaces the sleeve 82 away fromthe valve section 12, and forms a space 84 around the section I2. Thesection I2 therefore is a sliding valve plunger.

The other end of the sleeve 82 is recessed and threaded, and receives anannular shoulder 85 of a retaining ring 81. This ring 81 has an internalannular flange 89 which corresponds in depth to the flange 83, and anupstanding annular web 9| which abuts against the end of the sleeve 82.Shoulder 93 of the ring 81 is threaded and receives a retaining cap 95.

At each end of the space 84 there is provided a layer of suitablepacking 88, 98, each layer being sufiiciently thick to form an efiectiveseal against air leakage from the said space. A coil spring 88 iscompressed between these layers of packing sufficiently to retain thepacking positively in position without displacement as the sliding partI2 reciprocates during operation oi the apparatus. The spring 86 abutsagainst retaining members 91, 99, these retaining members being anchoredby a thin flange I8I, I83 retained in the packing. Packing I85 also isretained in place around the cap by a suitable resilient washer I8'Iwhich has a flange I89 anchored in the packing.

The housing 82 is provided with a flange 92 which is secured by screws94 to a second housing 96 which constitutes the nozzlehousing. Thenozzle 88 extends into this housing 98, and when in inoperativeposition, it is substantially flush with the outer face of the housing.

The face I88 of the housing 96 comprises a target against which the pipeis placed for blowing. It will be observed from Fig. 5 that the nozzle80 extends into a hole 98 which is positioned towards the bottom of thetarget faces I of the housing. This enables the accommodation of pipesof widely difl'erent diameters at the nozzle 80 for the blowingoperation.

It will be seen that the housing 98 is provided with a heavy base I02,the front of which has a conical concave depression I04 cut into it.This forms a guide for the pipe to be blown and enables the pipe to beplaced easily and directly at the proper position at the target face I00to admit the blowing nozzle into pipe. Suitable pipe guides such asindicated at I 06 and Figure 5 may be provided on the mounting frame,adjustment, therefore, being provided by a bolt I08 and nut I I0, whichallow the guide I06 to be positioned at the proper adjustment for agiven size of pipe being treated.

It will beseen also that top frame members I0 define ways upon which theentire assembly may travel. The valve 22 is shown as being mounted in abracket I I2 and is actuated by a treadle I I4, which treadle isoperated by the operator placing his foot upon it. The bracket II 2 ismovable along with the machine and pipes, and to allow the air lines toaccommodate themselves unrestrictedly to this movement, flexible airhose is used between the main air supply line I4 and all working airconnections.

Fig. 8 shows diagrammatically how the valve operates, and from this viewit will be seen that when in closed position the valve 22 maintains thesupply line 20 closed, and also the outlet line 24. When the treadle H4is depressed, lines 20 and 24 are brought into communication so that airfrom the flexible hose I8 will pass through hose 20 into hose 24 andthence into the rearward compartment of the actuating assembly B. Withan air pressure of 100 lbs. per sq. inch, for example, being maintainedin the line I4, the opening of the valve 22 will deliver substantially100 lbs. per sq. inch of pressure into this rearward compartment of theactuating assembly. At the same time, hose I4 is delivering air at 50lbs. pressure into the forward compartment of the air cylinder, this airbeing maintained automatically under substantially constant pressure.

The pipe 30, therefore, acts as a plunger which is controlled by theactuation of the three-way valve 22 which in turn is under manual (i.e., pedal) control of the operator. When, in accordance with theexample, the operator manipulates the valve 22 to feed into the rearcylinder compartment air under 100 lbs. pressure, this air acts inopposition to the air under 50 lbs. pressure in the forward cylindercompartment. This pressur differential moves the plunger head assembly Dtowards the left as viewed in Fig. 3.

This action moves pipe 30 to the left, and also the slide-valve plunger"I2, displacing the latter towards the left until ports 18 pass underflange 89, and, therefore, are brought into communication with eachother through the space 84, thus allowing air under the line pressure tobe blown through nozzle 80, which in the construction of Fig. 2 has beenmoved out from the housing into projecting position H6 in the pipe to betreated.

It will be seen that the control valve for the nozzle is free frommanually operated parts, but on the contrary, its only moving part isthe plunger 12 which is actuated by actuation of the remote valve 22.

When the operator removes his foot from the treadle I,I4, valve 22operates to bring lines 24 and 28 into communication, closing line 20.This releases the air in the rearward compartment of the assembly B andcauses the pressure entering through the line I4, which in theillustration is maintained constant at 50 lbs., to force the assembly Dand pipe 30 backwards and places the nozzle in retracted or idleposition. The air used in blowing the scale is direct line, or mill,pressure, usually about 100 lbs. per sq. inch.

It will be understood that in the course of production the mill iscalled upon to cut random and fixed lengths of pipe. Thus, in thepresent installation, the next operation following the scale blowing maybe a sawing operation for the purpose of simply removing crop ends ofrandom length pipe, or for the sawing of pipe to accurate fixed lengths.

' Thus, under certain circumstances, it is essen tial that the pipeleave the position of the scale blowing and approach the saws in a veryuniform and definite formation or alignment. This result is accomplishedin the present case, by so mounting the machine that the scale blowingapparatus is moved bodily along suitable ways as will be understood fromthe accompanying drawings. As will appear from the foregoing, thismovable feature includes the housing, the main air valve, the aircylinder, and the foot valve.

The operating table shown in the drawings consists of several parallelsteel rails over which the pipe supply rolls. As the pipes approach thescale blowing machine, the operator grasps each piece by hand and placesit against the target face of the housing for application of the air jetto the pipe. The rollers with anti-friction bearings are installed onthe said rails in line with the scale blowing machine, the rollersfacilitating the handling of the pipe and contributing to the speed ofthe operation.

Thus the foregoing construction enables the pipe to be suitably alignedagainst the face of the housing, and subsequent performance of the nextoperation on the pipe. The construction described above allows the pipeto leave the position of scale blowing and approach the saws in a veryuniform and definite formation or alignment, as has been pointed outabove.

This alignment is an important consideration, particularly where thepipes are to be finished by butt-welding them together. In thisprocedure, crop ends of the pipe are removed by high speed circularsaws. It is customary to cut of! more of the tong end of the pipe thanof the back end, since the tong end is rough and irregular, While theback is square and can be welded better. The practice varies, but theaverage length of crop is about 2 inches for the back end and 15 inchesfor the tong end. Pipe is carried by crane from a cooling table to astraightening machine, thence to saw table, and laid thereupon with theback end towards the operator. Here it is rolled out piece by piece bythe operator, placed against the target of the scale blower, and thescale removed. The pipe is then advanced to the saws by means of anendless chain conveyor without longitudinal displacement. Thus, bypredetermining the position of the target at the scale blower inreference to the leading saw the operator is able to advance the pipeforward to the saws and cut. any length of crop end desired. The secondsaw is placed rearwardly of the first saw and removes the crop from thetong end, thereby cutting the pipe to any required length.

Random lengths of pipe are made by'spacing the saws at a greaterdistance than the maximum length of finished pipe, cutting off one endof the pipe, and then manually shifting the pipe by quick visualinspection and cutting off the second or tong end.

For such purposes, it may be unnecessary to align the ends evenly andconsequently a protruding, nonreceding nozzle may be employed forperforming the scale blowing operations. a

This form of the device is illustrated in Fig. 7, wherein the nozzle 80'is threaded as is indicated at Ma into the housing 96 instead of intothe sliding valve section 12, the nozzle 80 therefore beingnonretractable. The valve section 12 is otherwise the same inconstruction and operation as has been described above and the samereference characters are used to represent coradapted to guide differentsizes of pipes to the said opening, a nozzle in the said opening, avalve housing removably secured to the inner side of the said abutmentmember, a slide valve member in the said housing for controlling asupply of compressed air for the nozzle, the said slide valve membercomprising a movable part of the control valve for the compressed airand the housing a complementary fixed part, means for supplyingcompressed air to the nozzle under line pressure, actuatinginstrumentalities for the valve operable by fluid pressure including aplunger and a housing therefor, mechanism for automatically maintainingcompressed air under a substantially constant pressure in the housing onone side of the plunger, means for maintaining air under varyingpressure on the opposite side of the plunger, pedal operated mechanismfor applying air under line pressure to the said means and formaintaining a continuous pressure differential on the plunger so thatwhen the said pedal operated mechanism is actuated to build up anair-pressure differential-higher than the said constant pressure, theplunger is moved to open the said slide valve to supply a flow ofcompressed air under line pressure to the nozzle and when the saidmechanism is operated I to reduce the air-pressure differential belowthe said constant pressure, the plunger is moved to close the said slidevalve to shut oi the fiow of compressed air to the nozzle, and a readilydemountable connection between the movable part of the slide valveand-the said plunger.

2. Apparatus for blowing scale and the like from metal pipes, whichcomprises the combination with a supply of compressed air, of plungermechanism including a pipe for transmitting air under pressure from thesupply thereof. to the pipe being blown, a plunger housing enclosing aportion of the pipe, means on the pipe within the housing defining aplunger head positioned in the plunger housing and having oppositesides, the said plunger head dividing the said housing into forward andrear compartments, instrumentalities for maintaining a supply of airunder constant pressure in the forward compartment of the plungerhousing in advance of the plunger head, the said constant pressure beingless than line pressure, a sliding valve part directly oonnected to theair-supply pipe, a complementary fixedly mounted valve housing enclosingthe sliding valve part, whereby upon introduction of air under linepressure'in the said rear compartment of the plunger housing, theplunger head and pipe are moved against the said constant pressure tobring the pipe into extended position relative to the plunger housing,thereby responsively moving the sliding valve part relative to itshousing to open an air passage from the air-transmitting pipe into thepipe being blown, retraction of the air-transmitting pipe relative tothe plunger housing responsively to release of pressure in the rearcompartment and consequent retracting movement of the plunger head underaction of the constant pressure in the forward compartment causingretractive movement of the sliding valve part in its housing intoclosing position for the said air passage, means for constantlysupplying air under line pressure into the said air-transmitting pipe,valve means selectively operable for introducing air under line pressureinto the rear compartment of the plunger housing and also for ventingthe said rear compartment to surrounding atmosphere for relieving thepressure in the said rear compartment, and pedal means for op eratingthe said valve under foot-pressure of an operator.

3. Apparatus for blowing scale or the like from metal pipes, whichcomprises the combination with a mounting platform, of a supply line forcompressed air for supplying compressed air under line pressure, amounting platform, an integral base plate secured to the platform, aportion of the base plate defining a rigid upstanding abutment memberintegral with the base plate and having an opening therethrough, thesaid abutment member having an outer side and an inner side, the outerside of the said abutment member including an upwardly extending guidesurface terminating adjacent to the said opening and adapted to guidedifferent sizes of pipes to the said opening, a nozzle in the opening, avalve housing removably but fixedly mounted on the inner side of theabutment member, a movable slide valve member in the said valve housingfor controlling a supply of compressed air for the nozzle, a plungerpipe directly connected to the slide member, a plunger housing, means onthe pipe within the plunger housing defining a plunger head dividing thehousing into a forward compartment and a rear compartment, a connectingpipe between the compressed air supply line and the said forwardcompartment, a reducing valve in the said supply line whereby air ismaintained in the said forward compartment under substantially constantpressure which is less than line pressure, a second compressed air linedirectly connecting the compressed air supply line to the interior ofthe plunger pipe, whereby the plunger pipe is maintained continuouslywith air under line pressure, a third compressed air line for supplyingair under line pressure from the compressed air supply line to the saidrear compartment in the plunger housing, a multiple way control valve inthe said third compressed air line, and pedalactuated valve mechanism inthe control valve for selectively introducing air under line pressureinto the rear plunger housing compartment for moving the plunger pipeinto advanced position against the constant pressure in the forwardplunger housing compartment, thereby automatically moving the said slidevalve member in the housing relative to the housing to open an airpassage from the plunger pipe through the said nozzle, thereby blowingair under line pressure through the pipe to be blown, further actuationof the pedal-actuated valve mechanism moving 10

